Chief medical officer Sir Liam Donaldson thrust the subject of organ donation to the top of the health debate recently, when he proposed that organs should be routinely taken for transplant unless the deceased had explicitly opted out of being a donor.

His comments were prompted by the ongoing shortage of human organs for transplant. There are currently 7,338 people on theUKtransplant list (as of13 August 2007), and these patients are dying at a rate of more than one a day while they wait for organs to be donated.

At the same time, as the British Medical Association points out: 'Bodies are buried or cremated complete with organs that could have been used to save lives.'

Objection to donation is not the root of the problem – opinion polls consistently demonstrate that 70-90 per cent of Britons are willing to donate organs after death. Yet putting this into practice seems to be another matter, and only 23 per cent of the population have actually signed up to the organ donor register.

At the heart of the matter is the issue of consent. In the wake of the scandal at Alder Hey Hospital, in which children’s organs were routinely taken without consent, the Human Tissue Act 2004 was introduced, coming into force in September last year. The core principle was that there should be no donation without explicit consent.

The act does allow a nominated representative to make donation decisions on a deceased person's behalf, and also introduced a statutory checklist of those in a 'qualifying relationship' who can consent to organ donation if the deceased did not express a view either way.

What Sir Liam has now proposed is a fundamental change from the position established by the act only a few years ago – suggesting legislation which would presume consent unless the deceased had opted otherwise.

This might take the form of a 'soft' opt out system, in which the family’s views could be taken into account, or a 'strong' opt out, where only the deceased person's registration of their own objection, through a central NHS database, would be sufficient to avoid donation.

A move to presumed consent may represent a practical solution to the organ shortage crisis, but is likely to attract opposition, as it opens up a number of ethical dilemmas that would need careful consideration ahead of any proposed legislation.

Sir Liam's proposal prioritises the social interest served by the availability of donor organs over that of the individual to control what happens to their body after death. It is debatable whether, in principle, consent really can be presumed. Might it be more honest to discuss a system of donation without consent? Those who object to any clinical intervention without explicit consent could see the proposals as the start of something more serious.

The very word 'donation' seems incompatible with something being taken rather than given. However, the language of 'harvesting' organs conjures up very different associations. These issues go to the heart of the extent to which the benefit of wider society should justify interference with our lives and our bodies.

Even if there can be presumed consent, the prospect may well sit less comfortably with some cultural, moral or religious views than others.

With this in mind, how informed is the public likely to be about the organ donation process to which they will be presumed to have consented? And how informed would they need to be?

Other interests may also need to be taken into account, such as the individual needs of patients waiting for transplants, the wishes of the family of the deceased person, and the efficient use of healthcare resources – kidney dialysis costs around£21,000 per quality adjusted life year, compared with a cost of around£4,700 to perform a kidney transplant.

Organ transplantation is possibly unique in modern medicine as a field where lives are lost every day for lack of a physical resource – human organs. The ethical and legal debate will no doubt roll on, but in the meantime, it is clear that the Human Tissue Act 2004 leaves this underlying problem unresolved.

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